Arrangement for operating a shut-off valve having a tapered plug

ABSTRACT

Arrangement for actuating shut-off valve with tapered plug, has housing in which hollow actuating cylinder is coaxially supported for rotation and with an actuating shaft aligned with the coaxial axis firmly attached. Output cylinder is coaxially arranged in hollow actuating cylinder. The output cylinder is movable relative to hollow drive cylinder axially and radially. Spindle is attached on output cylinder opposite actuating shaft and aligned with coaxial axis; tapered plug being fastened on end of spindle facing away from output cylinder. At least one radially outwardly directed pin is arranged on outer peripheral surface of output cylinder. Outer surfaces of housing and hollow actuating cylinder have each at least one guideway extending over radial sector of outer surfaces, with which pin is operatively connected as a respective sliding block. At least the guideway arranged in outer surface of hollow actuating cylinder is formed as a through-opening through which pin passes.

The invention relates to an arrangement for operating a shut-off valve having a tapered plug, which are used in particular in the chemical, in particular the petrochemical industry, for closing and opening lines carrying fluid flows.

Shut-off valves open or close the flow of a fluid in a pipe. Closing or opening the flow occurs by a 90° rotation of the shut-off element. Shut-off valves have a completely sealing structure.

The shut-off elements of a shut-off valve are called plugs. They are constructed as ball plugs or tapered plugs. Tapered plugs have advantages relating to their manufacture and advantageous shut-off features and are mainly used in shut-off valves for special applications in industrial plants.

An adjustment to intermediate positions is not provided for shut-off valves. The operating modes of shut-off valves are essentially limited to open or closed.

Shut-off valves can be used for all pipe gauges and pressure ratings. They have a minimum flow resistance, since flow is generally not deflected or constricted and the flow medium passes through the shut-off valve in the same way as through a straight pipe section.

Advantageous are also short actuating times because the shut-off element has only to perform a 90° rotation. The required 90° rotation of the operating spindle of the shut-off element in the gland seal has a more favorable leakage behavior compared to valves and gate valves. During actuation of the shut-off element, no or only small linear strokes occur in contrast to valves and gate valves, which has a positive effect on the life of the seal. It also improves the sealing properties. Shut-off valves are therefore frequently used in pipeline systems carrying toxic, flammable or otherwise hazardous fluids.

Disadvantageous are the following facts: The reliable shut-off function of shut-off valves may be inadequate due to contamination. Shut-off valves are unable to control the fluid flow. Furthermore, they take up a comparatively large space in a pipeline. When the shut-off valve is closed, a fluid residue remains in the bore of the shut-off element.

The operation of shut-off valves, which are the subject of the invention, is commonly performed by using electric, pneumatic or hydraulic actuators, with which the tapered plug as the shut-off element is rotated by a spindle from the closed to the open position or vice versa. A rotation angle of 90° is thereby realized.

Since the reliability of the shut-off function largely depends on the exact fit of the shut-off element in its seat, the close fit of the tapered plug in the seat initially requires considerable forces for rotating the tapered plug. This is disadvantageous, on one hand, because the respective electric, pneumatic or hydraulic actuating units as well as the force-transmitting spindle must be dimensioned commensurate with the large required torque, which results in increased material and labor costs as well as in increased installation space.

On the other hand, a rotation of the tapered plug with a tight fit in its seat performed with a large torque increases wear on the conical plug and seat surfaces, which in turn increases maintenance and repair expenses and the risk of a leak.

Numerous proposed solutions of the prior art are aimed at eliminating these disadvantages.

Thus, for example, the British publication GB 461 653 A proposes a solution wherein the tapered plug is raised slightly from its seat during its 90° rotation. In this invention, a nut is therefore integrated in the actuating element, which forms as a screw cap part of the actuating spindle and is coupled with the spindle by a lost motion coupling. In this way, rotation of the actuating spindle in the opening direction causes the tapered plug to rise from its seat before it is rotated into the open position. Conversely, a rotation of the actuating spindle in the closure direction pushes the tapered plug back down into its seat after returning to the closed position. The disadvantage of this solution is that the arrangement of the lost-motion coupling results in significant additional manufacturing and installation costs.

The British document GB 595 700 A also proposes an arrangement which is supposed to solve the problem associated with, on one hand, a high sealing pressure in tapered plugs and, on the other hand, a desired low operating torque during the rotation of the tapered plug. First, a tapered plug is provided having a pair of precisely mated conical surfaces in conjunction with strong axial springs at the spindle end, ensuring the desired sealing effect in the closed state of the shut-off valve. To relieve pressure during the rotation, the aforementioned shut-off valve has additional features which relieve the spring pressure during the rotation. This prevents wear of the conical surfaces of the seat and the tapered plug. At the instance when the valve is opened, the end bearing of the actuating spindle is completely relieved so that the tapered plug can be rotated without undue friction.

A tapered-plug valve of the aforedescribed type has as a relief mechanism a worm or helical gear acting on a relief cam, which due to its axial component adjusts the final pressure to the movement state. This proposed solution is also associated with significantly higher manufacturing and installation costs.

The current state of the industrial technology for reliable and gentle actuation of shut-off is represented by the so-called Wedge Torque Operator from the company PACIFIC VALVE [see PacificValvesWedgeplugBrochureCV-408.pdf].

The actuation concept of such tapered plug valve with a metal seal also includes

-   -   1. raising the tapered plug from the seat,     -   2. rotating the tapered plug by 90° and     -   3. lowering the tapered plug into the seat to restore leak         tightness of the valve.

This technically very demanding task is realized by way of a gear, such as the so-called Wedge Torque Operator or Lift-torque operator mentioned above. Whereas, like with a common gate valve, only a rotary actuator operates on the actuating spindle of the tapered plug, a gear connected below takes over the raising, rotating and lowering function of the actuating spindle with the tapered plug. The internal kinematics of this gear mechanism is complex, which in turn disadvantageously causes high production, assembly and maintenance costs.

It is therefore an object to develop an arrangement for actuating a shut-off valve with a tapered plug, wherein the movement necessary for a reliable and low-wear operation of the shut-off valve in order to raise, rotate and lower the actuating spindle with the tapered plug can be generated in a simple and low-cost manner.

This object of the invention is attained by the features of the independent claim, with additional dependent claims reciting advantageous embodiments of the invention.

An arrangement according to the invention for actuating a shut-off valve with a tapered plug has a housing in which a hollow actuating cylinder is coaxially and rotatably supported and on which an actuating shaft aligned with the coaxial axis is fixedly attached. An output cylinder is coaxially arranged in the hollow actuation cylinder. The output cylinder is supported for axial and radial movement with respect to the hollow actuating cylinder. A spindle is fixedly secured to the output cylinder along the coaxial axis in opposition to the actuating shaft, with a tapered plug attached on the end of the spindle facing away from the output cylinder. At least one radially outwardly directed pin is arranged on the outer peripheral surface of the output cylinder. The outer surfaces of the housing and of the hollow actuating cylinder each have at least one corresponding guideway extending over a radial sector of the output surfaces with which the pin is operatively connected in form of a corresponding sliding block. At least the guideway arranged in the outer surface of the hollow actuating cylinder is formed as a through-opening through which the pin passes.

The particular advantage of the invention is based on a very simple gear structure having few gear parts, with which the raising, rotating and lowering movement of the tapered plug required for reliable and low-wear operation of the shut-off valve can be realized.

In a preferred embodiment of the invention, two pins which are radially outwardly oriented in opposite directions are arranged on the outer peripheral surface of the output cylinder, wherein the outer surfaces of the housing and of the hollow actuating cylinder each have two guideways extending over radially opposing sectors of the peripheral surfaces with which the pin is connected in the form of a total of four sliding blocks.

Preferably, the guideways in the outer surface of the housing are also formed as through-openings.

In another preferred embodiment of the invention, a roller is arranged and positioned on the pin for rotation about the longitudinal axis of the pin so that the roller can be moved in the guideway disposed in the outer surface of the hollow actuation cylinder and implemented as a through-hole in the manner of a sliding block.

In a particularly preferred embodiment of the invention, two rollers which are spaced apart in the longitudinal axis of the pin and which are rotatable about the longitudinal axis of the pin are arranged and positioned so that one of the rollers is movable as a sliding block in the guideway formed as a through-opening in the outer surface of the hollow actuating cylinder, whereas the other roller is movable as a sliding block in the guideway formed as a through-opening in the outer surface of the housing.

The rollers are preferably constructed so that they can be rollably introduced into the guideways formed as through-openings along a longitudinal side of these through-openings. This is, for example, realized by making the outer diameter of the rollers smaller than the width of these through-openings.

Preferably, the hollow actuating cylinder may also be rotatably supported in the housing by roller bearings.

Advantageously, the housing is composed of an upper housing part and a lower housing part. The upper housing part has a housing cover with a through-opening for passage of the actuating shaft, whereas the lower housing part has a housing cover with a through-opening for the passage of the spindle.

With the application of the claimed arrangement for actuating a shut-off valve with a tapered plug, quite large savings in the manufacture and the maintenance of actuators for shut-off valve with tapered plugs can be attained by eliminating complicated gear structures while still attaining low-wear and low-maintenance operation of shut-off valves with tapered plugs.

Advantageously, in contrast to the conventional solutions, the space required by the claimed device for actuating a shut-off valve with tapered plug is also significantly reduced, thus allowing the actuators to have much smaller dimensions.

The invention will now be explained in more detail with reference to an exemplary embodiment.

The accompanying drawings show in

FIG. 1: a sectional view of an arrangement for actuating a shut-off valve with a tapered plug,

FIG. 2: a 3D-representation an arrangement for actuating a shut-off valve with a tapered plug,

FIG. 3: a 3D-representation of an arrangement for actuating a shut-off valve with a tapered plug, wherein the outer surface of the housing is not shown,

FIG. 4: a partially sectioned 3D-representation of an arrangement for actuating a shut-off valve with a tapered plug, and

FIG. 5: a schematic diagram of the movement of the pin in response to the rotation of the actuating cylinder relative to the housing.

FIG. 1 shows an arrangement for actuating a shut-off valve with a tapered plug. The arrangement includes a housing 1, composed of an upper housing part 1.1 and a lower housing part 1.2. The upper housing part 1.1 has a top cover 1.3 and the lower housing part 1.2 has a bottom cover 1.4. An axis 2 extends through the housing 1. The housing 1 of the arrangement for actuating a shut-off valve with a tapered cone is fixedly connected to the unillustrated valve body of the shut-off valve. The housing 1 is arranged coaxially with respect to the axis 2 of a hollow actuating cylinder 4, on which an actuating shaft 3 is fixedly attached. The actuating shaft 3 is passed to the outside through a through-opening in the top housing cover 1.3.

The hollow actuating cylinder 4 is arranged coaxially with the axis 2 in the housing 1 and supported for rotation about the axis 2. An output cylinder 5 is also arranged coaxially with the axis 2 in the hollow actuating cylinder 4. This output cylinder 5 is axially movable along the axis 2 and supported in the hollow actuating cylinder 4 for rotation about the axis 2.

A spindle 6 is affixed on the output cylinder 5 in opposition to the actuating shaft 3, with a tapered plug being rigidly attached at the end of the spindle 6 facing away from the output cylinder 5.

For the passage of the actuating shaft 3 and the spindle 6, the upper housing cover 1.3 and the lower housing cover 1.4 each have a through-opening. The output cylinder 5 has on its outer peripheral surface two pins 8 oriented radially outwardly in opposite directions with rotating rollers 9.1 and 9.2. The pins 8 are orthogonal to the axis 2. Each pin 8 supports two rotatable rollers 9.1 and 9.2, which can rotate independently from each other with a small spacing on their respective pin 8. The rotating rollers 9.1 and 9.2 are placed on the pin 8 so that they can roll on longitudinal sides of guideways 10 and 11, which are disposed as through-openings in the outer surfaces of the hollow actuating cylinder 4 and the housing 1 and which pass through or engage with the pins 8. The guideways 10 and 11 each extend over respective radial sectors of the peripheral surfaces of the housing 1 and the hollow actuating cylinder 4.

The rotatable rollers 9.1 and 9.2 can be rollably introduced into the through-openings forming the guideways 10 and 11 and have an outer diameter that is smaller than the width of the aforementioned through openings. The guideways 10 and 11 and the pins 8 with the rotatable rollers 9.1 and 9.2 arranged thereon are operatively connected in the form of a total of four sliding blocks.

FIG. 2 shows very clearly the roller 9.1 having an associated guideway 11 formed by a through-opening in the outer surface of the housing 1. This through-opening follows in its longitudinal side facing the tapered plug 7 a straight course, which has at both respective ends thereof in a curvy bulge in the direction of the tapered plug 7. FIG. 2 also illustrates that the rotatable roller 9.1 is constructed as a roller slidingly supported on the pin 8. In contrast, the roller 9.2 rolling on the guideway 10 is implemented on the pin 8 as a roller bearing.

A rotation angle α shows the possible rotation of the hollow actuating cylinder 4 in relation to the housing 1.

FIG. 3 shows a 3D-diagram of the arrangement for actuating a shut-off valve with a tapered plug 7, wherein the outer surface of the housing 1 has been omitted. Particularly clearly shown is the rotatable roller 9.2, which is formed as a roller bearing on the pin 8. The roller 9.2 rolls on the guideway 10 in the through-opening disposed in the outer surface of the hollow actuating cylinder 4, when the actuating cylinder 4 is rotated by the actuating shaft 3. The hollow actuating cylinder 4 is hereby supported relative to the housing 1 by the roller bearings 12. Its possible rotation relative to the housing 1 is also illustrated in FIG. 3 by the rotation angle α.

FIG. 4 shows a partially sectioned view of a 3D-diagram of an arrangement for actuating a shut-off valve with a tapered plug. FIG. 4 shows particularly clearly the coaxial arrangement of the output cylinder 5, the hollow actuating cylinder 4 and the housing 1. FIG. 4 also shows very clearly the arrangement of one of the two pins 8 radially protruding from the output cylinder 5 and its passage through the through-opening in the outer surface of the hollow actuating cylinder 4, and its engagement with the through-opening of the housing 1.

FIG. 5 shows schematically the movement of a pin 8 as a function of the displacement of the actuating cylinder 4 with respect to the housing 1, when a shutoff valve with a tapered plug is opened by the arrangement for actuating a shutoff valve with a tapered plug.

FIG. 5 includes the partial FIGS. 5 a to 5 j, which illustrate the movements of the guideways 10 and 11 and of the rollers 9.1 and 9.2 that are rotatably supported on the pin 8 for different rotation angles α the hollow actuating cylinder 4 with respect to the housing 1. The reference axis for the rotation of the hollow actuating cylinder 4 with respect to the housing is the axis 2.

The guideway 10 includes one region disposed orthogonal to the axis 2 and two mutually aligned regions in the direction of the axis 2. The guideway 11 has one region disposed orthogonal to the axis 2 and two regions disposed obliquely to the axis 2. The regions oriented obliquely to the axis 2 form an ascending and a descending region.

Partial FIG. 5 a shows the relative position of the guideways 10 and 11 to each other at a rotation angle α of the hollow actuating cylinder 4 relative to the housing 1 of α=0°. The rollers 9.1 and 9.2 are each located at the lowest point. The shut-off valve with the tapered plug 7 is closed and the outer surface of the tapered plug 7 is in fixed abutment with the seat surface.

Partial FIG. 5 b shows the relative position of the guideways 10 and 11 to each other at a rotation angle α of the hollow actuating cylinder 4 relative to the housing 1 of α=5°. The rotation of the hollow actuating cylinder 4 about this rotation angle α=5° forces the roller 9.1 to roll on the ascending part of the guideway 11 and to move both itself and the pin 8 carrying the roller 9.1 along the guideway 11. The roller 9.2 rolls on the guideway 10. The output cylinder 5 follows the movement of the pin 8 and rises, without rotating, in the longitudinal direction of the axis 2 commensurate with the guideway 11. The output cylinder 5 then lifts the tapered plug 7 out of the seat via the spindle 6. The outer surface of the tapered plug 7 is released from the seat surface.

As the partial FIGS. 5 c to 5 e show, during further rotation of the hollow actuating cylinder 4 relative to the housing 1, the pin 8 rotates about the axis 2 in addition being raised in the longitudinal direction of the axis 2. Therefore, the tapered plug 7 that is fixedly connected with the output cylinder 5 via the spindle 6 and was as described already raised from its seat, also rotates from the closed position toward the open position.

As shown in the partial FIG. 5 e, the roller 9.1 has reached the highest point of the ascending portion of the guideway 11 at a rotation angle of α=13° and transferred its movement via the pin 8 to the output cylinder 5, which has, in turn, raised the tapered plug 7 maximally via the spindle 6.

As shown in the partial FIGS. 5 f-5 i, when the hollow actuating 4 cylinder is rotated further in a rotation angle range 13°<α<115°, the pin 8 is not moved farther in the direction of the upper housing part 1.1, since due to the guiding of the rollers 9.1 and 9.2 in both guideways 10 and 11, the pin 8 can rotate only about the axis 2. Therefore, in the aforementioned rotation angle range of the hollow actuating cylinder 4, only a rotation of the output cylinder 5 and thus the tapered plug 7 is effected. The tapered plug 7 is thus rotated when in the raised position, so that the tapered plug 7 is moved from the closed to the open position with low wear.

As the diagram of the partial FIG. 5 j shows, upon further rotation of the hollow actuating cylinder 4 in the rotation angle range of 115°<α<130°, the pin 8 is again lowered, because the roller 9.1 rolls on the descending part of the guideway 11. Consequently, the output cylinder 5 supporting the pin 8 and the tapered plug 7 connected with the output cylinder 5 by way of the spindle 6 are also lowered. The output cylinder 5 is lowered in the longitudinal direction of the axis 2 without rotating about the axis 2, because the guideway 10 of the roller 9.2 allows only a vertical movement of the pin 8 in the illustrated range. The lowering movement of the tapered plug 7 moves the tapered plug 7 into its seat after rotation into the open position. The outer surface of the tapered plug 7 then abuts the seat surface.

This movement completes the low-wear opening of the shut-off valve with tapered plug 7. A rotation of the hollow actuating cylinder 4 relative to the housing 1 in the opposite direction, similar to the aforedescribed process, closes the shut-off valve with tapered plug 7 in a low-wear manner.

List of Reference Numerals

1 Housing

1.1 Upper housing part

12 Lower housing part

1.3 Housing cover

1.4 Housing cover

2 Axis

3 Actuating shaft

4 Hollow actuating cylinder

5 Output cylinder

6 Spindle

7 Tapered plug

8 Pin

9.1 Roller

9.2 Roller

10 Guideway

11 Guideway

12 Roller bearing

α Rotation angle 

1. An arrangement for actuating a shut-off valve with a tapered plug, the arrangement comprising a housing (1) in which a coaxially and rotatably supported hollow actuating cylinder (4) is arranged, an actuating shaft (3) aligned with the coaxial axis (2) is fixedly attached on the cylinder (4), an output cylinder (5) also coaxially arranged in the hollow actuating cylinder (4) and which is axially and radially movable with respect to the hollow actuating cylinder (4), a spindle (6) fixedly mounted on the output cylinder (5) and oriented along the coaxial axis (2) opposite to the actuating shaft (3), a tapered plug (7) affixed on the end of the spindle (6) facing away from the output cylinder (5), wherein at least one radially outwardly oriented pin (8) is arranged on the outer peripheral surface of the output cylinder (5), the outer surfaces of the housing (1) and of the hollow actuating cylinder (4) each have at least one guideway (10 and 11) extending over a radial sector of the outer surfaces, with which the pin (8) is operatively connected in the manner of a respective sliding block, and wherein at least the guideway (10) arranged in the outer surface of the hollow actuating cylinder (4) in formed as a through-opening through which the pin (8) passes.
 2. The arrangement for actuating a shut-off valve according to claim 1, wherein two pins (8) oriented outwardly in opposite radial directions are arranged on the outer peripheral surface of the output cylinder (5) and the outer surfaces of the housing (1) and of the hollow actuation cylinder (4) each have two guideways (10 and 11) extending over two radially opposite sectors of the outer surfaces, with which the pins (8) are operatively connected in a manner of a total of four sliding blocks.
 3. The arrangement for actuating a shut-off valve according to claim 1, wherein the at least one guideway (11) is also constructed as a through-opening in the outer surface of the housing (1).
 4. The arrangement for actuating a shut-off valve according to claim 1, wherein a roller (9.2) rotatable on the pin (8) about the longitudinal axis of the pin (8) is arranged and positioned so as to be movable in the manner of a sliding block in the guideway (10) formed as a through-opening in the outer surface of the hollow actuating cylinder (4).
 5. The arrangement for actuating a shut-off valve according to claim 3, wherein two rollers (9.1 and 9.2) rotatable about the longitudinal axis of the pin (8) are arranged on the pin (8), spaced apart on the pin (8) in the direction of the longitudinal axis of the pin (8), and positioned so that one of the rollers (9.2) is movable in form of a sliding block in the guideway (10) formed as a through-opening in the outer surface of the hollow actuating cylinder (4) and the other roller (9.1) is movable in form of a sliding block in the guideway (11) formed as a through-opening in the outer surface of the housing (1).
 6. The arrangement for actuating a shut-off valve according to claim 5, wherein the rollers (9.1 and 9.2) are constructed so that they can be rollably inserted into the guideways (10 and 11) formed as through-openings along a longitudinal side of these through-openings (10 and 11).
 7. The arrangement for actuating a shut-off valve according to claim 6, wherein the outer diameter of the rollers (9.1 and 9.2) is undersized compared to the width of these through-openings (10 and 11).
 8. The arrangement for actuating a shut-off valve according to claim 1, wherein the hollow actuating cylinder (4) is supported in the housing (1) by roller bearings (12)
 9. The arrangement for actuating a shut-off valve according to claim 1, wherein the housing (1) comprises an upper housing part (1.1) and a lower housing part (1.2).
 10. The arrangement for actuating a shut-off valve according to claim 1, wherein the upper housing part (1.1) comprises a housing cover (1.3) with a through-opening for passage of the actuating shaft (3) and the lower housing part (1.2) comprises a housing cover (1.4) with a through-opening for passage of the spindle (6). 